# What's that white coating on plums?

**URL:** <https://boards.straightdope.com/t/whats-that-white-coating-on-plums/221438>\
**Category:** Factual Questions\
**Created:** [December 28, 2003, 7:58pm UTC](https://boards.straightdope.com/t/whats-that-white-coating-on-plums/221438 "2003-12-28T19:58:37Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![Earthling](https://avatars.discourse-cdn.com/v4/letter/e/90db22/32.png) [@Earthling](https://boards.straightdope.com/u/Earthling)\
**Post date:** [December 28, 2003, 7:58pm UTC](https://boards.straightdope.com/t/whats-that-white-coating-on-plums/221438/1 "2003-12-28T19:58:37Z")

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And grapes. My web search turned up “glaucous,” which means “a powdery or waxy coating that gives a frosted appearance,” so that only re-states my question and is therefore not helpful.

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**Author:** ![herman\_and\_bill](https://avatars.discourse-cdn.com/v4/letter/h/f1d935/32.png) [@herman\_and\_bill](https://boards.straightdope.com/u/herman_and_bill)\
**Post date:** [December 28, 2003, 8:31pm UTC](https://boards.straightdope.com/t/whats-that-white-coating-on-plums/221438/2 "2003-12-28T20:31:08Z")

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I have always understood it to be yeasts.

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**Author:** ![donkeyoatey](https://avatars.discourse-cdn.com/v4/letter/d/e47c2d/32.png) [@donkeyoatey](https://boards.straightdope.com/u/donkeyoatey)\
**Post date:** [December 28, 2003, 9:01pm UTC](https://boards.straightdope.com/t/whats-that-white-coating-on-plums/221438/3 "2003-12-28T21:01:01Z")

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> [@](#):
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> You’ve probably seen a dull, powdery bluish-white coating on various fruits, including plums, apples, and grapes. This natural surface wax, called a “bloom,” is easily wiped off.

From [here](http://www.garden.org/courses/c1_preview.html).

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**Author:** ![Mister\_Rik](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mister_rik/32/491_2.png) [@Mister\_Rik](https://boards.straightdope.com/u/Mister_Rik)\
**Post date:** [December 28, 2003, 9:16pm UTC](https://boards.straightdope.com/t/whats-that-white-coating-on-plums/221438/4 "2003-12-28T21:16:45Z")

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> [@](#):
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> What’s that white coating on plums?

That’s plums too.